The present invention relates to methods and compositions that may be useful in subterranean operations, and more specifically, to certain emulsions and masses produced using those emulsions exhibiting improved permeability and stability, and methods of preparation and use in subterranean operations.
Hydrocarbon production from subterranean formations commonly involves, inter alia, drilling a well bore that penetrates the hydrocarbon-bearing formation, and producing hydrocarbon fluids (e.g., oil and/or gas) through the well bore to the surface. In some cases, treatment fluids also may be introduced into the well bore to perform a variety of functions, such as stimulating the production of hydrocarbon fluids from the formation, removing undesirable substances from the formation, facilitating the drilling of a well bore, and numerous other functions. Loss of treatment fluids into permeable portions of the subterranean formation may be undesirable since it may, inter alia, result in the reduction of fluid pressure below a level necessary for certain treatments, or may preclude the complete treatment of certain areas of the formation. When the formation is one that may be characterized as poorly or weakly consolidated, efficient treatment and hydrocarbon production may be complicated by, inter alia, well bore instability and the migration of sand and/or “fines” from the formation. Migration of fines (e.g., particles from the formation) along with produced fluids and treatment fluids may be undesirable since they may, inter alia, damage both downhole equipment and surface equipment, and typically must be disposed of in an environmentally-acceptable manner.
Conventional attempts to address the problems of well bore instability and formation fines migration have involved operations referred to as “gravel packing.” Typical gravel packing treatments involve suspending particulates (commonly referred to as “gravel particulates”) in a fluid, placing that fluid in the well bore, and depositing at least a portion of those particulates in a desired area in or near the well bore, e.g., near unconsolidated or weakly consolidated formation zones, to form a gravel pack. In general, a gravel pack is a grouping of particulates that are packed sufficiently close together so as to prevent the passage of certain materials through the gravel pack while having sufficient permeability to permit fluids (e.g., treatment fluids, produced fluids, etc.) to flow through. This gravel pack may, inter alia, enhance sand control in the subterranean formation and/or prevent the flow of particulates from an unconsolidated portion of the subterranean formation into a well bore. One common type of gravel-packing operation involves placing a screen in the well bore and packing the annulus between the screen and the well bore with the gravel particulates of a specific size designed to prevent the passage of formation fines. The gravel particulates act, inter alia, to prevent the sand and formation fines from occluding the screen or migrating with treatment fluids and produced fluids, and the screen acts, inter alia, to prevent the particulates from entering the well bore. The gravel particulates may also be coated with certain types of materials, including resins, tackifying agents, and the like, among other purposes, to enhance conductivity (e.g., fluid flow) through the gravel pack in which they reside. In some instances, expandable screens that can be expanded or inflated once placed inside a well bore to more closely fit against the walls of the well bore may be used in these treatments.
Conventional gravel packing operations, as well as operations involving the use of expandable screens, have been problematic. Bridging of sand particles within the gravel pack may occur, which may create voids within the gravel pack. Void spaces also may occur with expandable screens, wherein a well bore is drilled in a soft formation and formation material may be washed out in certain locations, which may enlarge the diameter of the bore hole in the washed-out regions. Installing screens and gravel packs in a well bore may be costly and time consuming, and may be impractical to use in certain applications, for example, in well bores that are too narrow to accommodate equipment necessary for the gravel packing treatment and other downhole operations.